The present invention relates to a stacked solid electrolytic capacitor and a stacked transmission line element.
A conventional solid electrolytic capacitor element is provided with a valve metal body at a central portion thereof. The valve metal body is formed by roughening, through etching, the surface of a metal plate made of an elementary substance of metal having a valve function, such as aluminum, tantalum, niobium, or titanium, or an alloy thereof, or formed by integrating together, through sintering, a metal plate having a valve function and metal powder having a valve function.
The solid electrolytic capacitor element has a structure wherein an oxide film is formed on the surface of the valve metal body, then insulating resin is formed thereon to divide a region into two regions, and then, in the region that will serve as a cathode portion, a solid electrolyte layer, a graphite layer, and a silver paste layer, or a solid electrolyte layer, a graphite layer, and a metal plating layer, or a solid electrolyte layer and a metal plating layer are stacked in the order named.
On the other hand, a conventional transmission line element is provided at a central portion thereof with a valve metal body like that of the solid electrolytic capacitor element. The transmission line element has a structure wherein an oxide film is formed on the surface of the valve metal body, then insulating resin is formed thereon to divide a region into three regions, and then, in the central region that will serve as a cathode portion, a solid electrolyte layer, a graphite layer, and a silver paste layer, or a solid electrolyte layer, a graphite layer, and a metal plating layer, or a solid electrolyte layer and a metal plating layer are stacked in the order named.
For achieving reduction in size, increase in capacity, and reduction in impedance with respect to the foregoing conventional solid electrolytic capacitor element or transmission line element, it is effective to stack a plurality of solid electrolytic capacitor elements or transmission line elements in a thickness direction and electrically connect them together.
The conventional stacking technique is disclosed in, for example, JP-A-H11-135367 (hereinafter referred to as “reference 1”). In a conventional stacked solid electrolytic capacitor, cathode portions are connected to each other via a conductive adhesive interposed therebetween, while anode portions are individually joined to a lead frame by resistance welding.
In the conventional stacking technique, however, inasmuch as the anode portions of the respective elements are joined to the lead frame, there has been a problem that when increasing the number of the stacking elements, the anode portion of the element located outermost is largely deformed to thereby degrade a characteristic of the element, and therefore, the number of the stacking elements may be two at maximum.